Yeah, what binkie said...
Check the disc for scratches. Even the slightest of scratches can prevent the DVD from being ripped. Since this is the first Shrek movie, I don't think there is any major copy protection on it, so AnyDVD and DVD Shrink should be able to handle it. The disc is probably either dirty or scratched or it is a bad press. Try cleaning the disc and then try ripping it again. If that doesn't work, it is probably a bad press. If it is a bad press, you won't be able to back up that disc. You'll have to get another original.

Copy Cat 2.0 actually skip the bytes which are not readable from file and copy all other bytes therefore it extracts max data which is normally not done by windows copy operation. Copy Cat can be helpful at times when you want to copy a CD or DVD which is scratched,when you want to copy data from harddisk area which is partially not readable

just got my kid shrek dvd antryed making a copy and yes its scratched but found on another system i have it has dvd dicripter on it and burned a copy with noproblem bur i added a copy of dvd regioncss dicripter to the other systems and it works!!!